A young lady named Miss Wonderly walks into the offices of Spade and Archer, Private Detectives. Miss Wonderly had just told Sam Spade why she needed to employ his services, when Miles Archer enters the room. Sam says "Miss Wonderly just told me her sister Corrine ran away with a guy named Floyd Thursby, and they are here in San Francisco. She wants Corrine away from Thursby because she believes he is dangerous. Miss Wonderly says that has a meeting with Thursby after 8 o'clock tonight in her hotel lobby. Archer agrees to be there to watch over her. Later that night, Police Lieutenant Duffy calls Sam and tells him that his partner Archer has been found in an alley, shot through the heart.